Certain relative large land-based vehicles, such as locomotives, transit vehicles, off-highway vehicles (e.g., mining trucks), and the like, include electric traction motors to provide the force to move the vehicle. In the case of a locomotive, a diesel engine drives an alternator, which supplies current to drive the traction motors, and which, in turn, propels the locomotive and any train cars attached thereto forward or backward. When propelled as such, a locomotive is said to be motoring. Further, the traction motors may change configuration to perform an additional function. In particular, once the locomotive is in motion, the traction motors may be configured to generate rather than consume electricity. As generators, the traction motors typically convert the locomotive's kinetic energy into electrical energy, and as a result, slow the locomotive. Using the traction motors to reduce speed is referred to as dynamic braking. A number of conventional locomotives do not store the generated electrical energy, but rather transfer the generated electricity to electrically resistive grids, also known as braking grids or a load box, to convert the electrical energy into heat energy, which is vented to the atmosphere via the resistive grids.
In addition, such resistive grids are also commonly used for “self-load” testing of the locomotive. Self-load testing refers to the use of the resistance grids as a form of a dynamometer or load bank to test the horsepower of the locomotive engine and/or the output of the alternator. During self-load testing, the generator output is delivered to the resistive grids instead of the traction motors while the locomotive is stationary. Thus, in known locomotives, the power (energy) produced during self-load testing is typically dissipated as heat by the resistance grids. The dissipating of heat is a waste of power, results in the dissemination of undesirable greenhouse gases, and provides no useful benefit.